Commercial customers often have a greater variety of flexible consumption applications, thereby causing higher loads than at their disposal and in comparison to residential customers. Thus, their flexibility potential is bigger and in most cases, many households would have to be contracted in load management schemes and equipped with ICT components to mirror the potential of just one commercial customer.
During the eTelligence field trial, the commercial customers were integrated into a Virtual power plant (VPP) which again acted on their behalf on an ICT-base marketplace.
Among several DER units, such as a wind park and a photovoltaics plant, two commercially used cold storage houses (250 kW and 260 kW) were integrated. The cold storage’s operators could significantly decrease their electricity costs by between 6 and 8 per cent respectively. These savings were realized by the virtual power plant’s operation system. The Virtual Power Plant sent optimized schedules to the operators of the cold storages based on when they could obtain particularly cheap amounts of electricity on the EPEX spot market. The Virtual Power Plant then bought the inexpensive electricity and the cold storage operators and followed the schedule indication to make best use of the situation. In most cases, however, the communication between Virtual Power Plant and commercial customers was automated and ICT based. The applications e.g. in the cold storages were connected to the overall ICT infrastructure in form of an IEC 61850 based energy management system (EMS) that later became the EWE product “intelligent load manager”. The management system sent the planned schedule, the so called “can-schedules” for the attached applications to the Virtual Power Plant Control room, which in turn modified the schedules based on the best obtainable energy prices and sent back the adapted “should-schedule” to the management device in the customer’s premises.
The field test took place over the course of the year 2011 and shed light on the development of network flexibility over the year due to changing seasons. At the end of the field trial, it became evident that at least in case flexibility based on thermal processes (such as cold storages), the flexibility potential was significantly greater during winter than during summer and that higher financial gains could thus be obtained during this time span. The lower temperatures increased the flexibility potential of cold storage units and thus, the virtual power plant had a greater variety of options for their scheduling efforts. Coincidentally, the prices on energy markets became increasingly fluctuating during the winter months, so that the virtual power plant could furthermore draw from a greater price optimization potential as well.
eTelligence marketplace and its interfaces, source: eTelligence 2012
Next to the financial benefits for the cold storage operators, the integration of the cold storage house has resulted in systemic benefits. Mistakes in generation prognoses calculated by the virtual power plant for the DER units connected to it could be diminished by adapting the schedules of the consumption applications controlled by the virtual power plant, such as the cold storage houses. The eTelligence field trial proved that the two cold storage houses served to reduce the prognosis mistake’s impacts down to a third of the damage that would occur without intervention.
Before eTelligence took up the work on integrating commercial customers into Smart Grid infrastructures, the standardised integration of these users was not possible. Throughout the project’s lifetime, however, the integration became increasingly easy and integration costs decreased as the development of IEC standard 61850 progressed. This standard was initially designed for the integration of DER units, yet it could also be applied to large consumption applications. In fact, after the conclusion of the eTelligence project, the integration costs for commercial consumption applications and thus flexibilities into Smart Grid infrastructures could be reduced and as a result, business scenarios drawing on the development could be planned in an increasingly cost effective manner.
The EWE “intelligent load manager” and the connected price optimization service for large commercial customers today belong to the product and service portfolio of EWE. The intelligent load manager fulfills the same tasks for the commercial customers that the virtual power plant fulfilled within the eTelligence trial.
However, today not only cold storage houses benefit from the product, but also other commercial customers, such as large green houses or supermarket chains, flour mills, bucket elevator pumps, waterworks as well as customers in the paper and cement industry. The EWE utility optimizes their applications’ schedules with the goal to pay the least expensive price for their consumption. One of the main prerequisites for the successful integration of commercial customers is the presence of applications with thermal flexibility potential. Other E-Energy projects such as model city Mannheim (moma) or MeRegio, have pointed into similar directions.
Furthermore, the eTelligence consortium could learn about the threshold consumption that helps to differentiate a customer that is sufficiently flexible for a successful integration from those whose flexibility cannot match the integration costs. The threshold was calculated at an annual consumption of at least 500.000 kWh.
eTelligence (Model Region Cuxhaven)
Dr. Tanja Schmedes, EWE Aktiengesellschaft
Donnerschweer Straße 22 – 26, 26123 Oldenburg